Computer pointing devices for positioning a cursor and entering commands into a computer are well known in the art. These devices typically include a body or top portion upon which the user's hand rests, two or three depressible control buttons integral with the body, and a bottom portion or base which contains a motion sensing device and electronics. Some computer pointing devices include a rotatable ball, wherein electronic encoders sense rotation of the ball and generate a signal indicative of the ball's rotation to control movement of a cursor on a computer screen. The rotatable ball extends from the bottom surface of the computer pointing device, and contacts a work surface such as a table or mouse pad. The movement of the computer pointing device across the work surface causes rotation of the ball, and therefore movement of the cursor. Other computer pointing devices employ optical encoders that track the motion of the pointing device over a work surface and generate a signal indicative of the pointing devices' position which is electronically coupled to the computer screen cursor.
After the cursor is appropriately positioned, the control buttons, sometimes referred to as keys or switches, permit the user to enter various commands into the computer. For example, depressing a control button may open an application program, highlight text in a word processing program, fire a weapon in a game, pull down a menu, open or close a file, and the like.
Many of the currently available computer pointing devices have disadvantages however. First, the computer pointing device may not fit the hand of the particular user, and therefore may cause discomfort or difficulty of operation. Additionally, prolonged use of the computer pointing device can cause biomechanical stress to the user. These factors may manifest themselves in several ways, some examples being, the hand or arm of the user may feel tired or cramped after grasping and operating the computer pointing device for any length of time. Or more seriously, repetitive stress injury (RSI), a cumulative trauma disorder stemming from prolonged repetitive, forceful, or awkward hand movements, may be experienced, with its' resultant damage to the muscles, tendons, and nerves of the neck, shoulder, forearm, and hand.
A need therefore exists for a computer pointing device which will both fit the hand of the particular user, and minimize any biomechanical stress experienced by the user. U.S. Pat. No. 5,731,807 discloses a computer pointing device which assists in realizing these two goals. This patent discloses an apparatus and method for customizing the shape of a computer mouse to an individual's hand. The device uses a pliable body, typically a pliable body with an elastomer skin enclosing a pliable material. The pliable body is shaped into a customized configuration. A bonding agent may be used with the pliable material to form a hardened, customized configuration. The pliable body is connected to an electonic base assembly, which includes electronic circuitry to generate a mouse output signal for application to a computer. U.S. Pat. Nos. 5,570,112, 5,576,733, 5,581,277, and 5,648,798 illustrate other ergonomic computer pointing devices.